The present invention relates to a synchronized alarm holding system, and more particularly to a synchronized alarm holding system wherein, when the same alarm is held and processed in different apparatuses, the difference between alarm processes in the apparatuses is eliminated, by synchronizing alarm processes in the apparatuses by means of a holding process part.
Recently, there has been a demand for a protection method wherein different apparatuses have the same displayed/held alarm state, when the display and output of the same alarm are held in different apparatuses. In actuality, when an alarm detection apparatus and an alarm processing apparatus are not embodied by the same apparatus, different apparatuses may have different displayed states and different held output states concerning the same alarm. Therefore, there is a need to realize a system wherein the displayed alarm states and the held alarm output states of different apparatuses are the same even when the alarm detection apparatus and the alarm processing apparatus are not embodied by the same apparatus.
An alarm holding system is a system whereby an occurrence of a failure in a processing apparatus or the like is indicated by lighting an LED for indicating a position at which a failure has occurred. The alarm holding system may light the LED for an extremely short period of time, or as long as any desired interval such as one second or one minute.
FIG. 1 shows the system construction of a conventional alarm holding system. The alarm holding system of FIG. 1 includes an alarm detection apparatus 100 and an alarm processing apparatus 200. The alarm detection apparatus 100 includes a detection part 110 for detecting an input alarm, a lighting holding process part 120 for holding a lighting by means of the detected alarm and a holding pulse, and a display/transfer part 130 for displaying and transferring the held alarm.
The alarm processing apparatus 200 includes an alarm detection part 210 for detecting an alarm from a signal received from another alarm detection apparatus or the alarm detection apparatus 100, a one-second holding timer 220 for holding a pulse for one second, and for sending the holding pulse to the lighting holding process part 120 of the alarm detection apparatus 100, a lighting holding process part 230, and a display part 240.
The conventional alarm holding system is configured such that the alarm detection apparatus 100 detects an alarm and sends the detected alarm to the alarm processing apparatus 200. The one-second holding timer 220 for transferring the alarm transfers the held pulse to the alarm detection apparatus 100 after a passage of one second is detected (the time can be arbitrarily set). The alarm detection apparatus 100 detects the held pulse and displays the alarm according to the timing at which the held pulse is detected.
However, the above described alarm holding system has a problem in that there is created a difference between the timing at which the alarm display is held in the alarm processing apparatus 200 by means of the holding pulse, and a timing at which the alarm display of the alarm detection apparatus 100 is held with the result that the alarm display state of the apparatuses show a difference.
FIG. 2 shows timings of pulses occurring in the conventional alarm holding system. In FIG. 2, (a) shows the output from the detection part 110 of the alarm detection apparatus 100. (b) shows the holding pulse sent from the one-second holding timer 220 of the alarm processing apparatus 200 to the lighting holding process part 120 of the alarm detection apparatus 100. (c) shows the output signal from the lighting holding process 120 part of the alarm processing apparatus 200. (e) shows the signal sent from the one-second holding timer 220 of the alarm processing apparatus 200 to the lighting holding process part 230. (f) shows the signal output from the lighting holding process part 230 to the display part 240. Referring to FIG. 14, because of the time difference between the signal shown in (b) and the signal shown in (e), and because of the time difference between the signal shown in (a) and the signal shown in (d), there is a lack of synchronization. Because the alarm output (c) shows a drop, the holding pulse of the alarm cannot be held by the alarm detection apparatus 100. Instead, the alarm processing apparatus 200 holds the alarm output signal. This arrangement may cause a malfunction to occur in the alarm holding system, thus creating a problem in alarm management of the apparatuses.